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J Perret

Publications and source records attributed to J Perret.

At least 73 records · Page 4Linked to original sources
PubMed1990

A polymorphic satellite sequence maps to the pericentric region of the bovine Y chromosome.

Exploiting a serendipitously observed bovine male-specific signal, generated by the mouse pSP64.2.5EI minisatellite probe, we have cloned a bovine (Bos taurus) Y-specific sequence: btDYZ-1. This sequence is composed of 60 tandem repetitions of a motif consisting of two parts: a 40-bp-long unit, showing a mean divergence of 27% between repeats, separated from the next repeat by a TG-rich stretch varying in length between 12 and 63 bp. The number of copies of this repeated motif has been estimated at 6 X 10(4) per male genome. As a consequence, the corresponding satellite, DYZ-1, might represent approximately 1/20 of the bovine Y chromosome. btDYZ-1 has been mapped by in situ hybridization to the pericentric region of the Y chromosome. It is characterized by a substantial genetic polymorphism and has been shown to be conserved within the Bos and Bison genera of the Bovinae subfamily. This sequence is being used to develop a sexing procedure for bovine preimplantation embryos based on the polymerase chain reaction.

Animals↗
PubMed1990

Diadenosine 5',5'''-P1,P4-tetraphosphate (AP4A) levels under various proliferative and cytotoxic conditions in several mammalian cell types.

Diadenosine 5',5'''-P1,P4-tetraphosphate (Ap4A) has been proposed as an intracellular signal for growth. In order to test this hypothesis Ap4A levels were followed in several cell types under various conditions. Quiescent dog thyroid cells in a primary culture were induced to proliferate by addition of a mixture of epidermal growth factor, thyrotropin and foetal calf serum; V79 cells were synchronized by serum depletion then stimulated to proliferate by addition of foetal calf serum. Protein and DNA synthesis increased in both cases, although no significant changes in Ap4A levels per cell could be demonstrated. HeLa D98/AH2 and L929 cells were treated with human recombinant tumour necrosis factor alpha which caused marked cell death. This was measured by a decrease in DNA content and a release into extracellular medium of incorporated radioactive precursor. No concomitant variations in Ap4A concentrations could be observed under these conditions. The data from these various systems do not support the hypothesis that changes in Ap4A levels regulate cellular proliferation.

Animals↗
PubMed1990

Prospective study of lacunar infarction using magnetic resonance imaging.

Using computed tomography and magnetic resonance imaging, we prospectively studied 100 patients hospitalized with a lacunar infarct. Our aim was to evaluate the capabilities of magnetic resonance imaging in the detection and delineation of lacunes in a project of clinicotopographic correlations. Seventy-nine patients had a classic lacunar syndrome; 35 had pure motor stroke, 26 had ataxic hemiparesis, seven had sensorimotor stroke, and 11 had pure sensory stroke. A miscellaneous group of 21 patients had less typical lacunar syndromes, primarily with brainstem signs and symptoms. Among a total of 153 lacunes, magnetic resonance imaging detected at least one lacune appropriate to the symptoms in 89 patients. In 16 patients at least two lesions correlated with the clinical features, and precise clinicotopographic correlations were possible in 68 patients. Magnetic resonance imaging was more effective when it was performed a few days after the stroke. Lesions causing different types of lacunar syndromes had significantly different volumes, suggesting that the size of the lesion may influence clinical features. Magnetic resonance imaging may be the imaging technique of choice in the study of lacunar syndromes.

Aged↗
PubMed1990

Hemiplegia in posterior cerebral artery occlusion.

We report 4 patients with hemiplegia due to a posterior cerebral artery occlusion. Associated clinical signs were aphasia, alexia or a neglect syndrome, hemianopia, and hemisensory loss. Hemiplegia was due to infarction in the lateral midbrain. The level of the occlusion in the posterior cerebral artery may be located distal to the junction with the posterior communicating artery.

Aged↗
PubMed1990

[Subcutaneous administration of apomorphine in motor fluctuations in Parkinson's disease].

Apomorphine, a dopaminergic agonist was given over a period of 12 months to 14 parkinsonian patients suffering from severe L-dopa induced on-off effects. Nine patients (mean age: 52 years; mean age at onset of the disease: 37 years), were treated by continuous infusion with a portable minipump, and 5 others by multiple injections with a penject. The mean duration of daily off periods was reduced by two thirds in all patients. The motor fluctuation intensity was only diminished in the 9 patients treated by continuous infusion. These patients received a mean apomorphine daily dose of 93 mg and L-dopa dosage was reduced by 53 p. 100. Red fibrous subcutaneous nodules occurred at the injection sites in all patients treated by infusion. This study confirms the effectiveness of subcutaneous apomorphine administration in the treatment of severe motor fluctuations.

Adult↗
PubMed1989

Cloning, sequencing and expression of the human thyrotropin (TSH) receptor: evidence for binding of autoantibodies.

A human thyroid cDNA library was screened by hybridization with a dog thyrotropin receptor (TSHr) cDNA. Sequencing of the resulting clones identified a 2292 residue open reading frame encoding a 744 amino acid mature polypeptide presenting 90.3% similarity with the dog TSHr. Two major transcripts (4.6 and 4.4 kilobases) were identified in the human thyroid which suggests that alternative splicing could generate multiple forms of human TSHr. Transfection of the coding sequence in COS-7 cells conferred to a membrane preparation of these cells the ability to bind specifically TSH. TSH binding was completely displaced by immunoglobulin preparations from patients with idiopathic myxoedema.

Amino Acid Sequence↗
PubMed1989

Molecular cloning of the thyrotropin receptor.

The pituitary hormone thyrotropin, or thyroid-stimulating hormone (TSH), is the main physiological agent that regulates the thyroid gland. The thyrotropin receptor (TSHR) was cloned by selective amplification with the polymerase chain reaction of DNA segments presenting sequence similarity with genes for G protein-coupled receptors. Out of 11 new putative receptor clones obtained from genomic DNA, one had sequence characteristics different from all the others. Although this clone did not hybridize to thyroid transcripts, screening of a dog thyroid complementary DNA (cDNA) library at moderate stringency identified a cDNA encoding a 4.9-kilobase thyroid-specific transcript. The polypeptide encoded by this thyroid-specific transcript consisted of a 398-amino acid residue amino-terminal segment, constituting a putative extracellular domain, connected to a 346-residue carboxyl-terminal domain that contained seven putative transmembrane segments. Expression of the cDNA conferred TSH responsiveness to Xenopus oocytes and Y1 cells and a TSH binding phenotype to COS cells. The TSHR and the receptor for luteinizing hormone-choriogonadotropin constitute a subfamily of G protein-coupled receptors with distinct sequence characteristics.

Amino Acid Sequence↗
PubMed1989

Pairs of cyclic AMP analogs, that are specifically synergistic for type I and type II cAMP-dependent protein kinases, mimic thyrotropin effects on the function, differentiation expression and mitogenesis of dog thyroid cells.

The role of the two different isozymes of the cAMP-dependent protein kinase is still unclear. We have investigated the potential roles for each isozyme in dog thyroid cells, a model in which the function, expression of differentiation and proliferation are positively regulated by thyrotropin acting through cyclic AMP. The dog thyroid contains both type I and type II cAMP-dependent protein kinases. These isozymes were selectively activated in vitro by type-I-directed and type-II-directed analog pairs. In thyroid slices, both type-I directed and type II-directed analog pairs synergistically activated thyroid hormone synthesis, as measured by incorporation of 131I into proteins and thyroid hormone secretion as determined by the release of butanol-extractable 131I. In primary cultures of dog thyroid cells both isozyme-directed analog pairs synergistically enhanced iodide trapping, a marker of differentiation, and DNA synthesis, as measured by the percentage of cells incorporating [3H]thymidine into their nuclei. However, DNA synthesis was more sensitive to type-I-directed pairs. The results demonstrate that both cAMP-dependent protein kinase isozymes can mediate the action of cAMP on function, differentiation expression and cell proliferation in dog thyroid cells.

Animals↗
PubMed1989

[Parkinson's disease and parkinsonian syndromes].

The parkinsonian syndrome rests on the clinical tripod: akinesia, rigidity, tremor. Akinesia is the key symptom, broadly defined as a difficulty in initiating and performing movements in proportion to their complexity (sophisticated, simultaneous movements) and their duration (repetitive movements). The most frequent cause of the syndrome is Parkinson's disease. Although this diagnosis needs to be confirmed in pathological terms by the loss of neurons and the presence of Lewy's bodies in the substantia nigra, some clinical data enable it to be envisaged with a minimum of errors; these are pure parkinsonian triad, good response to dopatherapy and asymmetrical symptoms. The other causes of parkinsonian syndrome are usually related to the administration of neuroleptic drugs and to degenerative diseases with lesions that are more diffuse than those of Parkinson's disease. In Steele-Richardson-Olzewski disease a parkinsonian syndrome is associated with supranuclear ophthalmoplegia. Multiple systematized atrophy presents under three different clinical aspects: a parkinsonian syndrome without tremor and resistant to L-dopa, suggesting atrophy of the strionigral tract; a parkinsonian syndrome associated with a cerebellar syndrome, suggesting olivo-cerebellar-pontine atrophy, and Shy-Drager disease which includes primary dysautonomy and other neurological syndromes.

Adult↗
PubMed1989

Phleomycin resistance as a dominant selectable marker for plant cell transformation.

Tobacco cells are sensitive to bleomycin and phleomycin. The Tn5 and the Streptoalloteichus hindustanus (Sh) bleomycin resistance ('Ble') genes conferring resistance to these antibiotics have each been inserted into two plant expression vectors. They are flanked by the nopaline synthase (nos) or the cauliflower mosaic virus (CaMV) 35S promoters on one side, and by the nos polyadenylation signal on the other. These four chimaeric genes were introduced into the binary transformation vector pGA 492, which were thereafter mobilized into Agrobacterium tumefaciens strain LBA 4404. The resulting strains were used to transform Nicotiana tabacum cv. Xanthi nc using the leaf disc transformation procedure. In all cases, phleomycin- and bleomycin-resistant tobacco plants were regenerated from transformed cells under selective conditions; however, the highest frequency of rooted plants was obtained when transformation was carried out with the 'Sh Ble' gene under the control of the 35S promoter. Phleomycin resistance was stably transmitted to sexual offspring as a dominant nuclear trait as confirmed by Southern blotting.

Bleomycin↗
PubMed1989

Pure sensory stroke due to a pontine lacune.

A 53-year-old hypertensive man presented with the sudden onset of an isolated lemniscal sensory syndrome of the entire left side of his body. Magnetic resonance images showed a small lacune in the right paramedian pons corresponding to the location of the medial lemniscus.

Cerebral Infarction↗
PubMed1989

[Alzheimer's disease and Parkinson's disease: neuropsychological differentiation].

54 patients with idiopathic Parkinson's disease (PD), 26 patients with Alzheimer's disease (AD) and 18 control subjects, all over 55, have performed neuropsychological tests, evaluating global intellectual function (Rosen's cognitive scale, WAIS digit symbol, WAIS similitude and WMS logical memory tests) and visuospatial functions (Rey lacunar pictures, Poppelreuter and Benton line orientation tests). AD group results were distinctly different from those of the PD and the control groups (p less than 0.001). In the PD group, only the Rosen's scale total score and the visuospatial tests were slightly altered (p less than 0.05). In a PD subgroup with a normal Rosen's scale result, the Benton line orientation test was different from controls (p less than 0.05). In another PD subgroup with Rosen's scale score comparable to a midly impaired AD subgroup, all the neuropsychological tests were abnormal. Only the WAIS digit symbol test, altered in this PD subgroup, was different comparing these 2 subgroups (p less than 0.05). With regard to the PD total group, the neuropsychological perturbed PD subgroup was older, had a longer duration of disease, a higher depression's score, less tremor and a worse equilibrium. These results might reflect a neuropsychological defect heterogeneity among PD patients, related to various pathophysiological hypothesis which are discussed in this paper.

Aged↗
PubMed1989

[Treatment of Parkinson tremor by chronic stimulation of the ventral intermediate nucleus of the thalamus].

Stereotactic ventral intermediate nucleus (Vim) thalamotomy may improve drug resistant severe parkinsonian tremor. However, tremor may recur and bilateral thalamotomy is known to induce unacceptable side effects in a proportion of patients. A high frequency (130 Hz) chronic Vim stimulation was performed in 4 parkinsonian patients, 2 of them having previously undergone a thalamotomy on the other side. Tremor was suppressed in all patients at the price of slight paresthesias. This improvement has been lasting from 2 to 14 months. Beneficial and adverse effects were suppressed at once each time the stimulation was stopped. These preliminary results are encouraging but a longer delay and more patients are obviously needed.

Adult↗
PubMed1989

[Chronic spinal amyotrophy involving the upper limbs in young adults (O'Sullivan and McLeod syndrome). MRI study of the cervical spinal cord].

In 5 cases of sporadic spinal muscular atrophy in young adults the muscular atrophy was localized in the hands and forearms. Age at onset ranged from 7 to 20 years. The duration of the disease was less than 5 years in 3 patients and more than 15 years in 2. Electromyography showed neurogenic anomalies in all wasted muscles, denervation potentials being also present in the proximal muscles of the upper limbs and distal muscles of the lower limbs in 2 patients. Motor nerve conduction velocity and sensory nerve action potentials were normal. Advantages of a topographic classification of the distal form of chronic spinal muscular atrophy are discussed. Spinal cord MRI was performed in 4 patients with a 0.5 Tesla superconducting magnet using surface coils, using a T1-weighted spin-echo technique (ET 26 ms; RT 500 ms) and a T2-weighted spin-echo technique (ET 90, 180 ms; 2,000 ms). With the T1 technique, axial MRI sections 7 to 9 mm thick of spinal cord showed a normal image between C1 and C4, and a flattened image between C5 and T1. This was considered as a possible spinal cord segmental atrophy.

Adolescent↗
PubMed1989

Magnetic resonance imaging in ischaemic accidents of the brain stem.

Seven cases of ischaemic accident affecting the brain stem are reported. There were two lacunar infarctions and five infarctions due to occlusion of major arteries (two lateral medullary infarctions, one pontine infarction and two thalamo-mesencephalic infarctions). In every case the abnormalities detected at MRI were concordant with the clinical findings. The authors underline the value of MRI in establishing clinico-topographic correlations in vivo and in differentiating lacunar infarctions from infarctions due to stenosis of major arteries in the vertebro-basilar system.

Aged↗
PubMed1988

[Spontaneous dissecting aneurysm of the internal carotid artery. Magnetic resonance imaging].

A man underwent Magnetic Resonance Imaging (MRI) of the left carotid artery 11 days after a spontaneous dissection of this vessel. T1 weighed images were obtained in the frontal and axial planes. There was a hyperintense lesion expanding the arterial wall due to the hematoma. The image of the lumen was narrowed. These findings corresponded to the angiographic abnormalities. In this case MRI was able to diagnose specifically and non invasively carotid artery dissections. Its sensitivity remains to be evaluated.

Aortic Dissection↗